/*
 *   This program is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation, either version 3 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/*
 *    Remove.java
 *    Copyright (C) 1999-2012 University of Waikato, Hamilton, New Zealand
 *
 */

package weka.filters.unsupervised.attribute;

import java.util.ArrayList;
import java.util.Enumeration;
import java.util.Vector;

import weka.core.Attribute;
import weka.core.Capabilities;
import weka.core.Capabilities.Capability;
import weka.core.DenseInstance;
import weka.core.Instance;
import weka.core.Instances;
import weka.core.Option;
import weka.core.OptionHandler;
import weka.core.Range;
import weka.core.SparseInstance;
import weka.core.Utils;
import weka.core.WeightedAttributesHandler;
import weka.core.WeightedInstancesHandler;
import weka.filters.Filter;
import weka.filters.StreamableFilter;
import weka.filters.UnsupervisedFilter;

/**
 * <!-- globalinfo-start --> An filter that removes a range of attributes from
 * the dataset. Will re-order the remaining attributes if invert matching sense
 * is turned on and the attribute column indices are not specified in ascending
 * order.
 * <p/>
 * <!-- globalinfo-end -->
 * 
 * <!-- options-start --> Valid options are:
 * <p/>
 * 
 * <pre>
 * -R &lt;index1,index2-index4,...&gt;
 *  Specify list of columns to delete. First and last are valid
 *  indexes. (default none)
 * </pre>
 * 
 * <pre>
 * -V
 *  Invert matching sense (i.e. only keep specified columns)
 * </pre>
 * 
 * <!-- options-end -->
 * 
 * @author Len Trigg (trigg@cs.waikato.ac.nz)
 * @version $Revision$
 */
public class Remove extends Filter implements UnsupervisedFilter, StreamableFilter, OptionHandler, WeightedAttributesHandler, WeightedInstancesHandler {

    /** for serialization */
    static final long serialVersionUID = 5011337331921522847L;

    /** Stores which columns to select as a funky range */
    protected Range m_SelectCols = new Range();

    /**
     * Stores the indexes of the selected attributes in order, once the dataset is
     * seen
     */
    protected int[] m_SelectedAttributes;

    /**
     * Constructor so that we can initialize the Range variable properly.
     */
    public Remove() {

        m_SelectCols.setInvert(true);
    }

    /**
     * Returns an enumeration describing the available options.
     * 
     * @return an enumeration of all the available options.
     */
    @Override
    public Enumeration<Option> listOptions() {

        Vector<Option> newVector = new Vector<Option>(2);

        newVector.addElement(new Option("\tSpecify list of columns to delete. First and last are valid\n" + "\tindexes. (default none)", "R", 1, "-R <index1,index2-index4,...>"));
        newVector.addElement(new Option("\tInvert matching sense (i.e. only keep specified columns)", "V", 0, "-V"));

        return newVector.elements();
    }

    /**
     * Parses a given list of options.
     * <p/>
     * 
     * <!-- options-start --> Valid options are:
     * <p/>
     * 
     * <pre>
     * -R &lt;index1,index2-index4,...&gt;
     *  Specify list of columns to delete. First and last are valid
     *  indexes. (default none)
     * </pre>
     * 
     * <pre>
     * -V
     *  Invert matching sense (i.e. only keep specified columns)
     * </pre>
     * 
     * <!-- options-end -->
     * 
     * @param options the list of options as an array of strings
     * @throws Exception if an option is not supported
     */
    @Override
    public void setOptions(String[] options) throws Exception {

        String deleteList = Utils.getOption('R', options);
        if (deleteList.length() != 0) {
            setAttributeIndices(deleteList);
        }
        setInvertSelection(Utils.getFlag('V', options));

        if (getInputFormat() != null) {
            setInputFormat(getInputFormat());
        }

        Utils.checkForRemainingOptions(options);
    }

    /**
     * Gets the current settings of the filter.
     * 
     * @return an array of strings suitable for passing to setOptions
     */
    @Override
    public String[] getOptions() {

        Vector<String> options = new Vector<String>();

        if (getInvertSelection()) {
            options.add("-V");
        }
        if (!getAttributeIndices().equals("")) {
            options.add("-R");
            options.add(getAttributeIndices());
        }

        return options.toArray(new String[0]);
    }

    /**
     * Returns the Capabilities of this filter.
     * 
     * @return the capabilities of this object
     * @see Capabilities
     */
    @Override
    public Capabilities getCapabilities() {
        Capabilities result = super.getCapabilities();
        result.disableAll();

        // attributes
        result.enableAllAttributes();
        result.enable(Capability.MISSING_VALUES);

        // class
        result.enableAllClasses();
        result.enable(Capability.MISSING_CLASS_VALUES);
        result.enable(Capability.NO_CLASS);

        return result;
    }

    /**
     * Sets the format of the input instances.
     * 
     * @param instanceInfo an Instances object containing the input instance
     *                     structure (any instances contained in the object are
     *                     ignored - only the structure is required).
     * @return true if the outputFormat may be collected immediately
     * @throws Exception if the format couldn't be set successfully
     */
    @Override
    public boolean setInputFormat(Instances instanceInfo) throws Exception {

        super.setInputFormat(instanceInfo);

        m_SelectCols.setUpper(instanceInfo.numAttributes() - 1);

        // Create the output buffer
        ArrayList<Attribute> attributes = new ArrayList<Attribute>();
        int outputClass = -1;
        m_SelectedAttributes = m_SelectCols.getSelection();
        if (m_SelectedAttributes.length == instanceInfo.numAttributes()) { // Nothing is being removed
            setOutputFormat(instanceInfo);
            initInputLocators(getInputFormat(), m_SelectedAttributes);
            return true;
        }
        for (int current : m_SelectedAttributes) {
            if (instanceInfo.classIndex() == current) {
                outputClass = attributes.size();
            }
            Attribute keep = (Attribute) instanceInfo.attribute(current).copy();
            attributes.add(keep);
        }
        // initInputLocators(instanceInfo, m_SelectedAttributes);
        initInputLocators(getInputFormat(), m_SelectedAttributes);
        Instances outputFormat = new Instances(instanceInfo.relationName(), attributes, 0);
        outputFormat.setClassIndex(outputClass);
        setOutputFormat(outputFormat);
        return true;
    }

    /**
     * Input an instance for filtering. Ordinarily the instance is processed and
     * made available for output immediately. Some filters require all instances be
     * read before producing output.
     * 
     * @param instance the input instance
     * @return true if the filtered instance may now be collected with output().
     * @throws IllegalStateException if no input structure has been defined.
     */
    @Override
    public boolean input(Instance instance) {

        if (getInputFormat() == null) {
            throw new IllegalStateException("No input instance format defined");
        }
        if (m_NewBatch) {
            resetQueue();
            m_NewBatch = false;
        }

        if (getOutputFormat().numAttributes() == 0) {
            return false;
        }
        Instance inst;
        if (m_SelectedAttributes.length == getInputFormat().numAttributes()) { // Nothing is being removed
            inst = (Instance) instance.copy();
            inst.setDataset(null);
        } else {
            double[] vals = new double[getOutputFormat().numAttributes()];
            for (int i = 0; i < m_SelectedAttributes.length; i++) {
                int current = m_SelectedAttributes[i];
                vals[i] = instance.value(current);
            }
            if (instance instanceof SparseInstance) {
                inst = new SparseInstance(instance.weight(), vals);
            } else {
                inst = new DenseInstance(instance.weight(), vals);
            }
        }

        copyValues(inst, false, instance.dataset(), outputFormatPeek());

        push(inst); // No need to copy
        return true;
    }

    /**
     * Returns a string describing this filter
     * 
     * @return a description of the filter suitable for displaying in the
     *         explorer/experimenter gui
     */
    public String globalInfo() {

        return "A filter that removes a range of" + " attributes from the dataset. Will " + "re-order the remaining attributes " + "if invert matching sense is turned " + "on and the attribute column indices " + "are not specified in ascending order.";
    }

    /**
     * Returns the tip text for this property
     * 
     * @return tip text for this property suitable for displaying in the
     *         explorer/experimenter gui
     */
    public String invertSelectionTipText() {

        return "Determines whether action is to select or delete." + " If set to true, only the specified attributes will be kept;" + " If set to false, specified attributes will be deleted.";
    }

    /**
     * Get whether the supplied columns are to be removed or kept
     * 
     * @return true if the supplied columns will be kept
     */
    public boolean getInvertSelection() {

        return !m_SelectCols.getInvert();
    }

    /**
     * Set whether selected columns should be removed or kept. If true the selected
     * columns are kept and unselected columns are deleted. If false selected
     * columns are deleted and unselected columns are kept.
     * 
     * @param invert the new invert setting
     */
    public void setInvertSelection(boolean invert) {

        m_SelectCols.setInvert(!invert);
    }

    /**
     * Returns the tip text for this property
     * 
     * @return tip text for this property suitable for displaying in the
     *         explorer/experimenter gui
     */
    public String attributeIndicesTipText() {

        return "Specify range of attributes to act on." + " This is a comma separated list of attribute indices, with" + " \"first\" and \"last\" valid values. Specify an inclusive" + " range with \"-\". E.g: \"first-3,5,6-10,last\".";
    }

    /**
     * Get the current range selection.
     * 
     * @return a string containing a comma separated list of ranges
     */
    public String getAttributeIndices() {

        return m_SelectCols.getRanges();
    }

    /**
     * Set which attributes are to be deleted (or kept if invert is true)
     * 
     * @param rangeList a string representing the list of attributes. Since the
     *                  string will typically come from a user, attributes are
     *                  indexed from 1. <br>
     *                  eg: first-3,5,6-last
     */
    public void setAttributeIndices(String rangeList) {

        m_SelectCols.setRanges(rangeList);
    }

    /**
     * Set which attributes are to be deleted (or kept if invert is true)
     * 
     * @param attributes an array containing indexes of attributes to select. Since
     *                   the array will typically come from a program, attributes
     *                   are indexed from 0.
     */
    public void setAttributeIndicesArray(int[] attributes) {

        setAttributeIndices(Range.indicesToRangeList(attributes));
    }

    /**
     * Main method for testing this class.
     * 
     * @param argv should contain arguments to the filter: use -h for help
     */
    public static void main(String[] argv) {
        runFilter(new Remove(), argv);
    }
}
